Diaphragm for electrochemical and electro-osmotic purposes



APPLICATION FILED MAY I6. 1914.

Patented Sept. 14, 1920'.

fig. II

M'fneSs 5 UNITED STATES PATENT-OFFICE.

BOTHO SCHWERI'N, OF FRANKFORT-ON-THE-MAIN, GERMANY, ASSIGNOR, BY MESNE.

ASSIGNMENTS, TO THE CHEMICAL FOUNDATION, INC., A CORPORATION OF DELA WARE.

DIAPHRAGM FOR ELECTROCHEMICAL AND ELECTRO-OSMOTIC PURPOSES.

Specification of Letters Patent. Patented Sept, 14, 1920,

Application filed May 16, 1914. Serial No. 839,085.

To all whom it may concern: I

Be ,it known that I, BOTHO SoHwn uN, a subject of the German Emperor, residing at Frankfort-on-the-Wlain, Germany, have invented certain new and useful Improvements in Diaphragms for Electrochemical and Electro-Osmotic Purposes, of which the following is a specification.

This invention relates to an apparatus for electro-chemical and electro-osmotic purposes. The apparatus consists in a vessel of suitable form containing the electrodes for the supply of the electric current and the substances to be treated. The electrodesare separated one from another by a diaphragm of suitable form in such a manner, that the electrical current flowing from one electrode to another must pass the diaphragm.

Diaphragms intended for electro-chemical or electro-osmotic purposes have hitherto consisted of clay, carbon, cement, asbestos, animal membranes, parchment paper and the like.

Diaphragms according to the present invention are particularly intended as substitutes for parchment paper. In using parchment paper it is often found, that disturbances and faults occur in the chemical or other processes which are due to the fact that the parchment paper is not uniform and perfect throughout, often containing perforations which in spite of their fineness permit substances to pass which ought to be retained.

It has now been found that regenerated cellulose made f r instance from viscose may be advantageously used as a material for making imperforate diaphragms. This material is free from the aforesaid disadvantages and may be brought into any desired form such as that of a cell.

In the acconi mnying drawings,

Figure I shows a cell in vertical section with the diaphragm also in section between the electrodes.

Fig. II is a vertical section of a modification.

In Fig. I, the receptacle is designated 1 'erated cellulose.

and the electrodes 2 and 3. The diaphragm 4 of regenerated cellulose is located between the electrodes. In Fig. II, the receptacle is shown at 5 and being of metal, it is designed to constitute one of the electrodes. The other electrode 6 is shown as being located within the tubular member 7 constituting 'a diaphragm and formed of regenerated cellulose.

Viscose is an aqueous solution of the sodium salt of cellulose xanthogenate, which is obtained by theaction of carbon disulfide on mercerized, unwashed cellulose. The cellulose present in the solution is again separated out by means of acids and ammonium salts, and this is known as regen- Regenerated cellulose ,is a kind of cellulose in which the natural fibrous structure is completely changed through chemical means, and is. altered into a completely homogeneous, purely colloidal and chemically uniform mass. This altered form of natural cellulose has the great advantage that diaphragms made of the regenerated cellulose are absolutely uniform, and therefore receii 'e the electric current uniformly through the entire mass.

A natural, unchanged fibrous cellulose is not uniform and therefore offers to the current as well as to the liquids to be separated certain resistances, so that differences develop during the operation of the current.

What I claim is:

A diaphragm "for use between the electrodes of an apparatus for electrochemical. and electro-osmotio purposes which consists of an imperforate, colloidal partition formed of cellulose which is regenerated and is homogeneous and chemically uniform so as to receive electric current uniformly throughout the entire mass.

In testimony whercogf affix my signature in the presence of two witnesses.

BOT HO SCHIVERIN.

Witnesses:

JEAN GRUND, CARL GRUND. 

